Abstract
Tidally driven flows, waves, and suspended sediment concentrations were monitored seasonally within a Zostera marina seagrass (eelgrass) meadow located in a shallow (1–2 m depth) coastal bay. Eelgrass meadows were found to reduce velocities approximately 60 % in the summer and 40 % in the winter compared to an adjacent unvegetated site. Additionally, the seagrass meadow served to dampen wave heights for all seasons except during winter when seagrass meadow development was at a minimum. Although wave heights were attenuated across the meadow, orbital motions caused by waves were able to effectively penetrate through the canopy, inducing wave-enhanced bottom shear stress (τ b ). Within the seagrass meadow, τ b was greater than the critical stress threshold (=0.04 Pa) necessary to induce sediment suspension 80–85 % of the sampling period in the winter and spring, but only 55 % of the time in the summer. At the unvegetated site, τ b was above the critical threshold greater than 90 % of the time across all seasons. During low seagrass coverage in the winter, near-bed turbulence levels were enhanced, likely caused by stem–wake interaction with the sparse canopy. Reduction in τ b within the seagrass meadow during the summer correlated to a 60 % reduction in suspended sediment concentrations but in winter, suspended sediment was enhanced compared to the unvegetated site. With minimal seagrass coverage, τ b and wave statistics were similar to unvegetated regions; however, during high seagrass coverage, sediment stabilization increased light availability for photosynthesis and created a positive feedback for seagrass growth.
Similar content being viewed by others
References
Abdelrhman, M.A. 2003. Effect of eelgrass Zostera marina canopies on flow and transport. Marine Ecology Progress Series 248: 67–83.
Ackerman, J.D., and A. Okubo. 1993. Reduced mixing in a marine macrophyte canopy. Functional Ecology 7: 305–309.
Benilov, A.Y., and B.N. Filyushkin. 1970. Application of methods of linear filtration to an analysis of fluctuations in the surface layer of the sea. Izvestya, Atmospheric and Oceanic Physics 6: 810–819.
Bouma, T.J., M. Friedrichs, P. Klaassen, B.K. van Wesenbeek, F.G. Brun, S. Temmerman, M.M. van Katwijk, G. Graf, and P.M.J. Herman. 2009. Effects of shoot stiffness, shoot size and current velocity on scouring sediment from around seedlings and propagules. Marine Ecology Progress Series 388: 293–297.
Bradley, K., and C. Houser. 2009. Relative velocity of seagrass blades: implications for wave attenuation in low-energy environments. Journal of Geophysical Research 114: F01004. doi:10.1029/2007JF000951.
Bricker, J.D., and S.G. Monismith. 2007. Spectral wave-turbulence decomposition. Journal of Atmospheric and Oceanic Technology 24: 1479–1487.
Bryan, K.R., H.W. Tay, C.A. Pilditch, C.J. Lundquist, and H.L. Hunt. 2007. The effects of seagrass (Zostera muelleri) on boundary-layer hydrodynamics in Whangapoua Estuary, New Zealand. Journal of Coastal Research SI50: 668–672.
Carr, J., P. D’Odorico, K. McGlathery, and P. Wiberg. 2010. Stability and bistability of seagrass ecosystems in shallow coastal lagoons: role of feedbacks with sediment resuspension and light attenuation. Journal of Geophysical Research 115: G03011. doi:10.1029/2009JG001103.
Carr, J.A., P. D’Odorico, K.J. McGlathery, and P.L. Wiberg. 2012. Modeling the effects of climate change on eelgrass stability and resilience: future scenarios and leading indicators of collapse. Marine Ecology Progress Series 448: 289–301.
Chen, Q., H. Zhao, K. Ju, and S.L. Douglass. 2005. Prediction of wind waves in a shallow estuary. Journal of Waterway, Port, Coastal, and Ocean Engineering 131: 137–148.
Chen, S., L.P. Sanford, E.W. Koch, F. Shi, and E.W. North. 2007. A nearshore model to investigate the effects of seagrass bed geometry on wave attenuation and suspended sediment transport. Estuaries and Coasts 30(2): 296–310.
de Boer, W.F. 2007. Seagrass–sediment interactions, positive feedbacks and critical thresholds for occurrence: a review. Hydrobiologia 591: 5–24.
Dean, R.G., and R.A. Dalrymple. 1991. Water wave mechanics for engineers and scientists. Singapore: World Scientific.
Duarte, C.M. 1991. Seagrass depth limits. Aquatic Botany 40: 363–377.
Fagherazzi, S., and P.L. Wiberg. 2009. Importance of wind conditions, fetch and water levels on wave-generated shear stresses in shallow intertidal basins. Journal of Geophysical Research 114: F03022. doi:10.1029/2008JF001139.
Fonseca, M.S., and J.S. Fisher. 1986. A comparison of canopy friction and sediment movement between four species of seagrass with reference to their ecology and restoration. Marine Ecology Progress Series 29: 15–22.
Fonseca, M.S., and M.A.R. Koehl. 2006. Flow in seagrass canopies: the influence of patch width. Estuarine, Coastal and Shelf Science 67: 1–9.
Gacia, E., and C.M. Duarte. 2001. Sediment retention by a Mediterranean Posidonia oceanica meadow: the balance between deposition and resuspension. Estuarine, Coastal and Shelf Science 52: 505–514.
Gacia, E., T.C. Granata, and C.M. Duarte. 1999. An approach to measurement of particle flux and sediment retention within seagrass (Posidonia oceanica) meadows. Aquatic Botany 65: 255–268.
Gambi, M.C., A.R.M. Nowell, and P.A. Jumars. 1990. Flume observations on flow dynamics in Zostera marina (eelgrass) beds. Marine Ecology Progress Series 61: 159–169.
Ghisalberti, M., and H. Nepf. 2006. The structure of the shear layer in flows over rigid and flexible canopies. Environmental Fluid Mechanics 6: 277–301.
Granata, T.C., T. Serra, J. Colomer, X. Casamitjana, C.M. Duarte, and E. Gacia. 2001. Flow and particle distributions in a nearshore seagrass meadow before and after a storm. Marine Ecology Progress Series 218: 95–106.
Grant, W.D., and O.S. Madsen. 1979. Combined wave and current interaction with a rough bottom. Journal of Geophysical Research 84: 1797–1808.
Gruber, R.K., and W.M. Kemp. 2010. Feedback effects in a coastal canopy-forming submersed plant bed. Limnology and Oceanography 55(6): 2285–2298.
Hansen, J.C.R., and M.A. Reidenbach. 2012. Wave and tidally driven flows in eelgrass beds and their effect on sediment suspension. Marine Ecology Progress Series 448: 271–287.
Jing, L., and P.V. Ridd. 1996. Wave-current bottom shear stresses and sediment resuspension in Cleveland Bay, Australia. Coastal Engineering 29: 169–186.
Kaimal, J., and J. Finnigan. 1994. Atmospheric boundary layer flows: their structure and measurement. New York: Oxford University Press.
Koch, E.W., and G. Gust. 1999. Water flow in tide- and wave-dominated beds of the seagrass Thalassia testudinum. Marine Ecology Progress Series 184: 63–72.
Koch, E.W., J.D. Ackerman, J. Verduin, and M. van Keulen. 2006. Fluid dynamics in seagrass ecology—from molecules to ecosystems. In Seagrasses: biology, ecology and conservation, ed. A.W.D. Larkum, R.J. Orth, and C. Duarte, 193–225. Amsterdam: Springer.
Lacy, J.R., and S. Wyllie-Echeverria. 2011. The influence of current speed and vegetation density on flow structure in two macrotidal eelgrass canopies. Limnology and Oceanography: Fluids and Environments 1: 38–55.
Lawson, S.E., P.L. Wiberg, K.J. McGlathery, and D.C. Fugate. 2007. Wind-driven sediment suspension controls light availability in a shallow coastal lagoon. Estuaries and Coasts 30(1): 102–112.
Lawson, S.E., K.J. McGlathery, and P.L. Wiberg. 2012. Enhancement of sediment suspension and nutrient flux by benthic macrophytes at low biomass. Marine Ecology Progress Series 448: 259–270.
Lowe, R.J., J.R. Koseff, and S.G. Monismith. 2005. Oscillatory flow through submerged canopies: 1. Velocity structure. Journal of Geophysical Research 110: C10016. doi:10.1029/2004JC002788.
Lu, S.S., and W.W. Willmarth. 1973. Measurements of the structure of the Reynolds stress in a turbulent boundary layer. Journal of Fluid Mechanics 60: 481–571.
Luhar, M., J. Rominger, and H. Nepf. 2008. Interaction between flow, transport and vegetation spatial structure. Environmental Fluid Mechanics 8: 423–439.
Luhar, M., S. Coutu, E. Infantes, S. Fox, and H. Nepf. 2010. Wave-induced velocities inside a model seagrass bed. Journal of Geophysical Research 115: C12005. doi:10.1029/2010JC006345.
McGlathery, K., I.C. Anderson, and A.C. Tyler. 2001. Magnitude and variability of benthic and pelagic metabolism in a temperate coastal lagoon. Marine Ecology Progress Series 216: 1–15.
Moore, K.A., R.J. Orth, and J.F. Nowak. 1993. Environmental regulation of seed germination in Zostera marina L. (eelgrass) in Chesapeake Bay: effects of light, oxygen and sediment burial. Aquatic Botany 45: 79–91.
Nepf, H.M. 1999. Drag, turbulence, and diffusion in flow through emergent vegetation. Water Resources Research 35(2): 479–489.
Nepf, H.M. 2012. Flow and transport in regions with aquatic vegetation. Annual Review of Fluid Mechanics 44: 123–142.
Nepf, H.M., J.A. Sullivan, and R.A. Zavistoski. 1997. A model for diffusion within emergent vegetation. Limnology and Oceanography 42(8): 1735–1745.
Nepf, H., M. Ghisalberti, B. White, and E. Murphy. 2007. Retention time and dispersion associated with submerged aquatic canopies. Water Resources Research 43: W04422. doi:10.1029/ 2006WR005362.
Orth, R.J., and K.J. McGlathery. 2012. Eelgrass recovery in the coastal bays of the Virginia Coast Reserve, USA. Marine Ecology Progress Series 448: 173–176.
Orth, R.J., M.L. Luckenbach, S.R. Marion, K.A. Moore, and D.J. Wilcox. 2006. Seagrass recovery in the Delmarva Coastal Bays, USA. Aquatic Botany 84: 26–36.
Orth, R.J., K.A. Moore, S.R. Marion, D. Wilcox, and D. Parrish. 2012. Seed addition facilitates Zostera marina L. (eelgrass) recovery in a coastal bay system (USA). Marine Ecology Progress Series 448: 177–195.
Peterson, C.H., R.A. Luettich Jr., M. Fiorenza, and G.A. Skilleter. 2004. Attenuation of water flow inside seagrass canopies of differing structure. Marine Ecology Progress Series 268: 81–92.
Raupach, M.R., J.J. Finnigan, and Y. Brunet. 1996. Coherent eddies and turbulence in vegetation canopies: the mixing-layer analogy. Boundary-Layer Meteorology 78: 351–382.
Sand-Jensen, K. 2008. Drag forces on common plant species in temperate streams: consequences of morphology, velocity and biomass. Hydrobiologia 610(1): 307–319.
Stapleton, K.R., and D.A. Huntley. 1995. Seabed stress determinations using the inertial dissipation method and the turbulent kinetic energy method. Earth Surface Processes and Landforms 20: 807–815.
Trowbridge, J.H. 1998. On a technique for measurement of turbulent shear stress in the presence of surface waves. Journal of Atmospheric and Oceanic Technology 15: 290–298.
Verduin, J.J., and J.O. Backhaus. 2000. Dynamics of plant–flow interactions for the seagrass Amphibolis antarctica: field observations and model simulations. Estuarine, Coastal and Shelf Science 50: 185–204.
Vogel, S. 1981. Life in moving fluids. Boston: Grant.
Ward, L.G., W.M. Kemp, and W.R. Boynton. 1984. The influence of waves and seagrass communities on suspended particulates in an estuarine embayment. Marine Geology 59: 85–103.
Wiberg, P.L., and C.R. Sherwood. 2008. Calculating wave-generated bottom orbital velocities from surface-wave parameters. Computer and Geosciences 34: 1243–1262.
Wiberg, P.L., and J.D. Smith. 1983. A comparison of field data and theoretical models for wave current interactions at the bed on the continental shelf. Continental Shelf Research 2: 147–162.
Widdows, J., N.D. Pope, M.D. Brinsley, H. Asmus, and R.M. Asmus. 2008. Effects of seagrass beds (Zostera noltii and Z. marina) on near-bed hydrodynamics and sediment resuspension. Marine Ecology Progress Series 358: 125–136.
Acknowledgments
We thank A. Schwarzschild, C. Buck, B. Rodgers, and D. Boyd for field assistance, and J. Bricker for helpful discussions regarding wave–turbulence decomposition. This research was funded by the National Science Foundation (NSF-DEB 0621014, BSR-8702333-06, DEB-9211772, DEB-94118974, and DEB-0080381) to the Virginia Coast Reserve Long-Term Ecological Research program and by NSF-OCE 1151314. J.C.R. Hansen was supported through an NSF graduate research fellowship (DGE-0809128).
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Hansen, J.C.R., Reidenbach, M.A. Seasonal Growth and Senescence of a Zostera marina Seagrass Meadow Alters Wave-Dominated Flow and Sediment Suspension Within a Coastal Bay. Estuaries and Coasts 36, 1099–1114 (2013). https://doi.org/10.1007/s12237-013-9620-5
Received:
Revised:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s12237-013-9620-5